1. Field of the Invention
The present invention relates to a method for treatment of allergic diseases, inflammatory diseases, diseases treatable by an antihistaminic agent, diseases treatable by a leukotriene antagonist, diseases treatable by a platelet activating factor antagonist and diseases treatable by bronchodilatation which comprises administering a 15-dehydroxy-16-oxoprostaglandin compound to a subject.
Nowadays, it is well established that histamine is acting as a chemical mediator in allergic and inflammatory diseases. Leukotrienes, compounds known as the slow reacting substances (SRS), are also known to be mediators in various biological reactions. Furthermore, it has recently been demonstrated that the slow reacting substances (SRS) such as leukotrienes involve in autoimmune diseases (AID). Also, the platelet activating factor (PAF) is being accepted as a chemical mediator in allergic and inflammatory reactions.
Presently, antihistaminic agents are widely used in the treatment of various allergic and inflammatory diseases. Although anti-lipoxigenases, substances inhibiting production of leukotrienes, and platelet activating factor antagonists have also been attempted in treatment of these disease, satisfactory results have not been obtained.
Prostaglandins (hereinafter, prostaglandins are referred to as PGs) are members of a class of organic carboxylic acid that are contained in human and most other mammalian tissues or organs and that exhibit a wide range of physiological activities. Naturally occurring PGs possess as a common structural feature the prostanoic acid skeleton: ##STR1## Some synthetic analogues have somewhat modified skeletons. The primary PGs are classified based on the structural feature of the five-membered cycle moiety into PGAs, PGBs, PGCs, PGDs, PGEs, PGFs, PGGs, PGHs, PGIs and PGJs, and also on the presence or absence of unsaturation and oxidation in the chain moiety as:
______________________________________ Subscript 1 13,14-unsaturated-15-OH Subscript 2 5,6- and 13,14-diunsaturated- 15-OH Subscript 3 5,6- 13,14- and 17,18- triunsaturated-15-OH ______________________________________
Further, PGFs are sub-classified according to the configuration of hydroxy group at position 9 into .alpha.(hydroxy group being in the alpha configuration) and .mu. (hydroxy group being in the beta configuration).
2. Background Information
Some 15-dehydroxy-16-oxoprostaglandin compounds are disclosed in Japanese patent application No. 55930/1991 (U.S. patent application No. 660,833/07, European patent application No. 91301480.9) .
As stated above, the activities of the primary PGs are diversified an one compound has various activities coexistently. While the fact that a compound has various activities appears to be advantageous at first sight, the presence of activities which are not useful in individual cases is not desirous because they are disliked as side-effects. Therefore, it is desirous to develop compounds having only one particular activity or a limited number of activities out of various activities of PGs. Furthermore, there is a continuous demand for the compounds of this kind which have improved chemical stability and reduced rate of metabolic degradation in the living body in comparison with the natural PGs. It has now been found that, as a results of extensive study seeking for such compounds, 15-dehydroxy-16-oxoprostaglandin compounds have excellent activities such as antiallergic, antiinflammatory, antihistaminic, leukotriene-antagonistic, platelet activating factor antagonistic and bronchodilatative activities.